Chondrogenesis of Adipose-Derived Stem Cells on Irradiated Cartilage

Background: Irradiated allogeneic costal cartilage is an alternative option of cartilage graft in patients with insufficient autologous cartilage. However, complications can occur during long-term follow-up. This study investigated whether Tutoplast-processed cartilage, one of the irradiated allogeneic costal cartilages, acts as a scaffold for adipose-derived stem cells and chondrogenesis. Methods: In vitro setting, human adipose-derived stem cells seeded onto Tutoplast-processed cartilage were cultured in chondrogenic medium and observed using a scanning electron microscope. Next, 3 types of irradiated cartilage-including Tutoplast-processed cartilage, undifferentiated stem cells on Tutoplast-processed cartilage (undifferentiated group), and chondrogenic differentiated stem cells on Tutoplast-processed cartilage (chondrogenic group)-were implanted subcutaneously into nude mice. Gross, histologic, and gene expression analyses of Tutoplast-processed cartilages were performed at postoperative weeks 2 and 4. Results: Human adipose-derived stem cells subjected to in vitro three-dimensional culture differentiated into chondrocytes and expressed cartilage-specificgenes. Adipose-derived stem cells seeded onto Tutoplast-processed cartilage were differentiated into chondrocytes in chondrogenic medium. In the chondrogenic group, the chondrogenic-differentiated cells attached to the surface of the Tutoplast-processed cartilage were maintained during the follow-up and were distinct from the existing Tutoplast-processed cartilage. Moreover, the chondrogenic group had higher expression of cartilage-specific genes compared with the undifferentiated group. Conclusions: Adipose-derived stem cells seeded onto Tutoplast-processed cartilage underwent chondrogenic differentiation, generating new cartilage, which was maintained after implantation without critical complications. The findings are clinically valuable in terms of overcoming the limitations of irradiated allogeneic costal cartilage, and broaden the surgical options for treatments requiring cartilage.